Super Mario Advance 4 Easter Egg - Hidden Luigi "Choose a Game" screen

Start "Super Mario Advance 4". Skip the intro, press single player on the title screen. Then you will be given to options: play "Super Mario Bros 3." or "Mario Brothers". Don't click any.
Notice when you scroll between the two options, Mario runs in and appears next to the titles. Press down, he'll run off the "Super Mario Bros. 3" option, and then appear on the "Mario Bros." title. Get the idea?
When Mario is next to the "Super Mario Bros. 3" title, click the up and down buttons repeatedly, and then stop at the "Mario Bros." screen. Luigi will appear!
This may take a few times, though.